The work relates to our understanding of the biochemical events associated with the normal function of the thyroid and to pathological conditions of the thyroid, such as in Graves' disease. The work began with a study of the effect of thyrotropin (TSH) on iodide transport mechanisms. The work has evolved in several directions: (1) the role of phospholipid metabolism in calcium mobilization, iodide efflux, and ligand-stimulated growth; (2) a detailed study of protein synthesis reflecting mRNAs induced by TSH and cyclic AMP; and (3) effects on iodide fluxes that can be related to, and reflect receptor activation by, a variety of ligands. The work continues to support the hypothesis that alterations in ion fluxes are important early events, as well as primary actions of TSH and pharmacological agents.